Re: [PATCH -v3 0/15] x86: Remove support for TSC-less and CX8-less CPUs

Ahmed S. Darwish
2025-12-15T13:55:32Z

Hi,

On Sun, 14 Dec 2025, Brian Gerst wrote:
>
> Does this also eliminate all processors that do not support CPUID?
>

If it does, then we can also remove X86_FEATURE_CPUID from word 3:

--- linux.orig/arch/x86/include/asm/cpufeatures.h
+++ linux/arch/x86/include/asm/cpufeatures.h
@@ -94,3 +94,3 @@
#define X86_FEATURE_NONSTOP_TSC ( 3*32+24) /* "nonstop_tsc" TSC does not stop in C states */
-#define X86_FEATURE_CPUID ( 3*32+25) /* "cpuid" CPU has CPUID instruction itself */
+/* Reserved ( 3*32+25) */
#define X86_FEATURE_EXTD_APICID ( 3*32+26) /* "extd_apicid" Extended APICID (8 bits) */

plus its call sites.

Thanks,
Ahmed